GSEA: improve color code of KEGG pathways

KEGG pathways are overlayed with a color code that should represent differential gene expression. This code is flawed by the fact that some boxes/entities are associated with several genes and the abs.max over genes was color encoded without information on the fact that it's several genes and which expression of which gene is displayed by color. The new version of cp_enrichment improves on this and now it makes clear i) if there are several genes associated to a box/entity ii) what is the diff. expression of all these genes iii) color codes these diff. expressions in a coherent way so user can interpret the color codes.